This achievements requires you to earn 30,000Cr with the
2008 Porsche #7 Penske Racing RS Spyder Evo, you can do this online or offline though this will be faster offline.
The car costs
2,000,000Cr but if you race online you can use the stock version for free.
To do this offline quickly go to:
-Career
-Go Race
-Event List
The Porsche events are 2 far left columns, the bottom right event of these 2 has fast events for this car.
Any bonuses earned will also count for the 30,000CrNote, my method takes 2 races instead of the same track going in circles, seems more fun to me and faster.